Grinding chain tool



Jan. 20, 1959 Filed Sept. 6, 1957 A. STlHL GRINDING CHAIN TOOL 3 Sheets-Sheet 1 Jan. 20, 1959 A. STIHL 2,869,534

GRINDING CHAIN TOOL Filed Sept. 6, 1957 3 Sheets-Sheet 2 Jan. 20, 1959 A sum 2,869,534

GRINDING CHAIN TOOL Filed Sept. 6, 1957 3 Sheets-Sheet s muv lllllllli 'u'inlu United States Patentfi ice GRINDTNG CHAIN TOOL Andreas Stihl, Neustadt, near Waiblingen, Germany Application September 6, 1957, Serial N o. 682,4G3

Claims priority, application Germany September 11, 1956 8 Claims. (Cl. 12s z1 The present invention relates to chain saw-like grinding tools for grinding rock and the like, in which the chain links of substantially T-shaped cross section carry abrasive elements having embedded therein for instance minute diamonds or similar hard abrasive granular ma-.

terial.

The heretofore known chain links of this type are relatively difficult to manufacture and have the further drawback that the abrasive material is not sufi iciently supported so that it happens again and again that the abrasive elements break out of the chain links. This is particularly the case when the chain links encounter shocks as it happens when rock with numerous cavities is being cut or ground.

It is, therefore, an object of the present invention to provide a motor operable chain saw-like grinding tool for grinding or cutting rock, which will overcome the above mentioned drawbacks.

It isanother object of this invention to provide a motor operable chain saw-like grinding tool for cutting or grinding rocks in which the chain is so designed that it is protected against strong shocks encountered when working rocks with numerous cavities.

It is a further object of this invention to provide a motor operable chain saw-like grinding tool as set forth in the preceding paragraphs, in which a lateral bending of the chain elements will be prevented.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

Fig. .1 is a side view of a chain link according to the present invention.

Fig. 2 is a cross section taken along the line II-II of Fig. 1. r

Figs. 3 to 5 show in a manner similar to that of Fig. 2 cross sections through three modified chain links.

f Fig. 6 is a side view of a chain link prior to receiving the abrasive or cutting element.

Fig. 7 is a side. view of a portion of a grinding tool according to the invention with the chain links somewhat modified over those of Figs. 1 and 6.

Fig. 8 isda top view of the chain section shown in Fig. 7.

Fig. 9 illustrates a side view of a chain link used in the lateral rows of links in Figs. 7 and 8 but without the abrasive element therein.

Fig. 10 is a section along the line XX through Fig. 9.

Fig. 11 is a side view of the chain link of Fig. 9 with the abrasive element therein.

2,869,534- Patented Jan. 20, 1959 Fig. 12 is a cross section through Fig. 11 taken along the line XI---XI.

Fig. 13 is a cross section similar to Fig. 12 through a chain link pertaining to the other lateral row of links of Fig. 8.

Fig. 14 represents a cross section through an intermediate chain link with the abrasive element overhanging the left side of the chain link with regard to Fig. 14.

Fig. 15 is a cross section through two lateral chain links in working position.

Fig. 16 is a cross section through an intermediate chain link with the abrasive element overhanging on the righthand side (with regard to Fig. 16) of the link.

Fig. 17 illustrates similar to Fig. 8 a top view of a modified grinding tool with the grinding elements of the lateral chain links overhanging on both sides of the respective links.

Fig. 18 is a cross section along the line XVIII-XVIII of Fig. 17.

Fig. 19 illustrates similar to Figs. 8 and 17 a top view of a modified grinding tool, according to which only every other link of the rows of links located opposite to each other carries a grinding element.

General arrangement The drawbacks outlined above of the heretofore known grinding tools of the type involved have been overcome according to the present invention by designing the chain link carrying the abrasive element in form of a fiat metal piece wnicnis provided with a cutout having a bottom section and two lateral sections or shoulders while the abrasive element is fitted into said cutout and rests against said lateral sections or shoulders. Thus, the cutting or grinding pressure is absorbed by one of said shoulders. in this way the manufacture of the entire chain link is considerably simplified while the shearing stress at those portions where the grinding element is soldered or other- Wise connected to the link proper is considerably reduced or entirely eliminated if the completely pre-shaped grinding eiement 18 inserted into the previously heated chain link.

in certain instances, namely when working rocks with numerous cavities, the grinding saw according to the invention is so to be designed that the abrasive elements Will be protected against strong shocks. Such shocks which exert a considerable stress upon the chain are caused when a plurality of successive grinding chain elements simultaneously lose contact with the bottom of the groove being sawed or ground into the rock. in such an instance the chain link in or over a cavity cannot be held any longer in its position by tue adjacent links but is pressed into the cavity. in this way it hits the wall of the cavity in a shock-like manner which cannot be absorbed any longer in a resident manner by the chain so that the chain is liable to break. In order to prevent such a situation, the grinding element is inserted and fitted into the supporting chain link and is provided with an inclined contacting surface and has its thickness re duced to such an extent that it will fill only a portion of the width of the groove to be cut for instance one-third to one-half thereof. The grinding saw according to the invention adapted also successfully to cut or grind rock with numerous cavities is characterized primarily in that in addition to the intermediate chain links, also lateral cha n links are provided with grinding elements. The arrangement is such that the grinding element is inserted between inclined edges up to the top in cutouts in the chain links and has a width forming a fraction only of the width of the groove to be cut while the total spacing between the outer lateral surfaces of said grinding elements at least approximately equals the-total width of the grcove to be cut.

According to a further development of the invention, the grinding elements of the lateral chain links rotrude beyond the central lane of the res ective chain link while the lateral chain links aligned with each other in transverse direction are placed adjacent each other in such a way that there remains only a small gap between the grinding elements of each pair of transversely aligned chain links, for instance a few tenths of a millimeter. In this way a lateral bending of the chain links toward each other will be prevented or at best limited to a few tenths of a millimeter. Such lateral bending of the chain links carrying the grinding elements would be liable to occur when lateral forces act upon the chain links as may in particular occur when starting a cut or grind into slate rock or the like.

Structural arrangement Referring now to the drawings in detail, the chain link with the cutting or grinding element comprises the link member 1 with the exchangeable rings 2 having a bore 3 therethrough for the rivets. The lower portion of the link 1 is provided with a follower cam 4. The link 1 has a cutout 9 (Fig. 6) with two shoulders 5, 5'. The grinding element 6 is provided with a groove 60 having a width corresponding to the thickness of the link 1 and is fitted from the top over the link 1 so that it fits into the cutout 9 and has its end faces 7 rest against the shoulders 5, 5' while with its lower edges it straddles the link slightly. If the grinding member is inserted into the link with small play or under pre-tension and is additionally soldered, welded or otherwise connected to the link. the grinding member 6 is so firmly anchored in the link 1 that it cannot detach itself from the link even when subjected to considerable shocks during the grinding operation. The sheet-like links 1 are considerably simpler and cheaper than the T-shaped links of heretofore known grinding chain tools. While the grinding element 6 is somewhat more voluminous than grinding elements of similar heretofore known chain tools, and thus may be slightly more expensive than the latter, in the long run this does not mean higher costs for the chain because the main advantage of the grinding element 6 remains maintained even after considerable wear of its upper grinding surface and the worn grinding element may be used later in connection with the making of new grinding elements.

Instead of the cross section according to Fig. 2, it is also possible in order to save material for the grinding element to employ profiles according to Figs. 3, 4 or 5 or similar forms with corresponding cross sections 6, 6" or 6' for the grinding element. A particularly firm bond or seat of the grinding element 6 with or in the chain link is obtained when the link 1 prior to the insertion of the grinding element 6 is preheated to a considerable extent so that the shoulders 5 and 5' when again cooling off will firmly press the grinding element therebetween.

The lower or bottom portion 61 of the cutout 9 may also be provided with grooves, teeth or the like in order to aid in the anchoring of the grinding element inserted into the cutout.

Figs. 7 to 16 illustrate the construction of the chainhke grinding tool according to the invention as it is particularly suitable for chain-like grinding tools to be used in connection with rocks having numerous cavities.

According to the embodiment illustrated in Figs 7 to 16, the chain has three rows of links. The chain link 1a of the intermediate or central row has two bores 3a, the

exchangeable ring 2a, the cam follower 4a and the grinding element 6a with minute diamonds and other hard materials embedded therein. The chain links 1a, la are connected with the respective adjacent links 11, 11 by means of rivets 10 which may also be hollow rivets. The chain links 11, 11' are located in the outer or lateral rows of chain links and, in conformity with the present invention, are likewise equipped with grinding elements designated with the reference numeral 6b. The grinding elements 6a, 6b have been inserted into their respective links up to their upper surface between the inclined edges a and b. In other words, the upper edge of the inserted grinding elements is substantially fiush with the adjacent upper edge portions of the links so that the inserted grinding elements are protected against shocks. The grinding elements 6a, 6b are held in the cutouts 9 from three sides and are expediently additionally anchored to the links by soldering, welding or in any other convenient manner. This connection may be further improved or reinforced by designing the grinding elements 6a, 6b in such a way that they laterally overlap the bottom portion of the cutouts 9. The grinding elements 6a and 6b are in this way protected not only against shocks when passing through cavities in rocks, but because they have a smaller width than the total width of the groove to be cut into the rock, they are also specifically less subjected to stresses. They are adapted to slide without clamping along the rock dust accumulating in the groove being cut by the chain-like grinding tool.

It is expedient to provide the grinding elements 6a and 6b with free cutting angles in such a way that they will be wider at the top or outer end portions than at the bottom or lower end portions.

Furthermore, when grinding chain tools are involved which move in one direction only, it is advantageous to provide the cutting elements with a free cutting angle in the cutting or grinding direction of the tool. In such an instance, the grinding elements have a wider front end face than the rear end face. In order to facilitate the mass production of the grinding elements, it is advantageous to give the same identical shape and size regardless of whether they are intended for the lateral rows or the intermediate row of chain links.

By designing the grinding elements 6a, 6b in such a way that they are wider than the chain links themselves and by causing said grinding elements laterally to overlap the bottom portion of .the cutout 9, a large contact surface for the welding, soldering or the like will be obtained.

When the grinding elements 6a, 6b protrude laterally toward the outside, the chain will cut itself completely free. The width of the groove in the rock will thus be wider than the thickness of the chain at the thickest portion thereof at the rivets. The lateral protrusion of the grinding elements 6a of the intermediate row of links prevents the formation of a ridge, seam of burr in the groove inasmuch as a small strip of the groove will be worked by both the intermediate row of chain links In, 1'11 and the lateral rows of chain links 11, 11'. Nevertheless, the grinding elements 6a are completely identical in size and shape and difier from each other only in that they are inserted so that they alternately have their laterally protruding portion on one side or the other side of the links of the intermediate row. Similar remarks apply to the grinding elements 6b of the lateral rows, which means that the grinding elements 6b of one lateral row are arranged so as to form the image of the grinding elements 6b of the other lateral row of chain links.

The design of the grinding elements in conformity with Figs. 17 and 18 is particularly favorable when strong lateral forces act from the outside upon the chain and tend to bend the upper portion of the chain links with the grinding elements toward the inside of the chain. By such bending forces acting upon the chain links 11, 11' of the lateral rows, the rivets 10 are subjected to high stress and in most instances are torn out. Therefore, with chain tools of the type involved which have to work for instance in slate or the like it is advantageous to design the grinding elements in such a way that they protrude also toward the inside as shown in Figs. 17 and 18 and to make the distance between these inwardly protruding portions of the grinding elements 6b so small, preferably only two-tenths of a millimeter that the respective grinding elements 6b aligned with each other in transverse direction of the chain will mutually support each other when they are bent toward the inside.

The chain tool links according to the present invention do not require broad ribs or the like at the upper side so that they can be designed with even thickness with the result that they can be mass produced as stampings. This further contributes to the reduction in the manufacturing costs of such chain links.

The ring member 2 protects the chain link not merely against lateral abrasive forces but also forms an effective reinforcement for the chain links 11, 11 of the lateral rows inasmuch as the rings 2 are firmly pressed against said links by the rivets (see Figs. 8 and 18). This effect may furthermore be improved by designing the ring member 2 somewhat wider than the intermediate chain link 6a and by causing the ring member to extend into corresponding cutouts or depressions on the chain links of the lateral rows as is illustrated in Figs. 14 to 16.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each comprising a plurality of spaced chain links, an intermediate link row interposed between said lateral link rows, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said lateral rows, each of said links extending in the direction of movement of said chain tool and each of the links of said lateral rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted in said cutouts and fixedly connected to said links while resting against the side portions of the respective cutout, each grinding element in the cutouts of said lateral rows of links having an outwardly directed portion extending beyond the bottom portion of the respective cutout and in a direction away from the latter.

2. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each comprising a plurality of spaced chain links, an intermediate link row interposed between said lateral link rows, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said lateral rows, each of said links extending in the direction of movement of said chain tool and each of the links of each of said rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted in said cutouts and fixedly connected to said links while resting against the side portions of the respective cutout, each grinding element in the cutouts of all of said rows of links having an outwardly directed portion extending beyond the bottom portion of the respective cutout and in a direction away from the latter.

3. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each comprising a plurality of spaced chain links, an intermediate link row interposed between said lateral link row-s, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said 1ateral rows, each of said links extending in the direction of movement of said chain tool and each of the links of each of said rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted in said cutouts and fixedly connected to the respective links while resting against the the side portions of the respective cutout, each grinding element in the cutouts of said lateral rows of links having an outwardly directed portion extending beyond the bottom portion of the respective cutout and in a direction away from the latter, while the grinding elements in the cutouts of said intermediate row of links likewise provided with a lateral portion extending beyond the bottom portion of the respective cutout have said lateral portion arranged alternately on one side and the other side of the respective links of said intermediate row of links.

4. An arrangement according to claim 1, in which the width of each grinding element of two transversely aligned chain links of the lateral rows of links is less than the width of the groove to be ground into the rock.

5. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each com prising a plurality of spaced chain links, an intermediate link row interposed between said lateral link rows, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said lateral rows, each of said links extending in the direction of movement of said chain tool and only every other link of each of said lateral rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted into said cutouts and fixedly connected to the respective link while resting against the side portions of the respective cutout, each grinding element in the cutouts of said lateral rows of links having an outwardly directed portion extending beyond the bottom portion of the respective cutout and in a direction away from the latter, the arrangement being such that only one of each two transversely aligned links of said lateral rows is provided with a cutout and a grinding element therein.

6. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each comprising a plurality of spaced chain links, an intermediate link row interposed between said lateral link rows, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said lateral rows, each of said links extending in the direction of movement of said chain tool and each of the links of each of said rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted in said cutouts and fixedly connected to said links while resting against the side portions of the respective cutout, all grinding elements in all of said cutouts of said links having substantially identical shape and size and having an outwardly directed portion extending beyond the bottom portion of the respective cutout and in a direction away from the latter.

7. In combination in a grinding chain tool for grinding rock and the like: two lateral link rows each comprising a plurality of spaced chain links, an intermediate link row interposed between said lateral link rows, a plurality of pivot means respectively pivotally connecting each link of said intermediate row with two adjacent and in transverse direction of said chain tool aligned links of said lateral rows, each of said links extending in the direction of movement of said chain tool and each of the links of said lateral rows being provided with a cutout having a bottom portion and two oppositely located side portions, and a plurality of grinding elements respectively fitted in said cutouts and fixedly connected to said links while resting against the side portions of the. respective cutout, each grinding element; in the cutouts of said lateral row of links straddling the respective link pertaining thereto, each pair of grinding elements pertaining to the respective transversely aligned links of the lateral rows of chain links having those portions there of which face each other arranged in onlyslightly spaced relationship to each other so as to be able to contact each other when slightly bending in transverse direction to the movement of said chain tool.

8. An arrangement according to claim 7, in which the spacing of those surfaces of said grinding elements which belong to transversely aligned chain links and face each other is within the range of a few tenths of a millimeter.

References Cited in the file of this patent UNITED STATES PATENTS 

